The same day, Turkish media published images of an alleged 15-member Saudi "assassination squad" and video of suspicious movements at the Saudi Consulate in Istanbul following Khashoggi's disappearance, putting new pressure on the kingdom amid growing global concern for the writer.

The State Department didn't respond to Fox News request for a comment.

Turkey's foreign minister said authorities would search the consulate in Istanbul as part of its investigation into Khashoggi's disappearance, saying Saudi officials were "open to cooperation", although it's unclear when the event would take place.

One of the first images from the CCTV footage shared by 24 TV broadcaster on Wednesday showed a man believed to be Khashoggi enter the consulate at 1.14pm (5.14pm in Thailand).

A squad of 15 Saudi Arabian men reportedly flew to Turkey just in time for Khashoggi's visit to the consulate for paperwork to marry his Turkish fiancée.

The official said that most or all of the 15 men held roles in the Saudi government or security services.

Public access flight trackers show one of the planes heading to Dubai on its way to Riyadh.

"He did not mind walking into the Saudi Consulate in Istanbul because he did not believe that something bad could happen on Turkish soil".

Khashoggi had written a series of columns for the Washington Post that were critical of Saudi Arabia's assertive Prince Mohammed, who has led a widely publicised drive to reform the conservative Sunni monarchy but has also presided over the arrests of activists and businessmen.

Even in exile he refused to outright condemn the Saudi regime, especially on alleged war crimes in Yemen and the crackdown on dissent back in Saudi Arabia. "He disappeared in December 2017 but his detention was not made official until his conviction and sentence were announced", said RSF. The two soon agreed to marry, but in order to do so he needed to finalise his divorce with his first wife in Saudi Arabia.

Saudi Arabia has called the allegations that it killed 59-year-old Khashoggi "baseless", but has offered no evidence over the past seven days to show that he ever left the building.

According to the Washington Post, U.S. intelligence "intercepted communications of Saudi officials discussing a plan to capture" Khashoggi, a prominent critic of Saudi Arabia's regime. Hatice Cengiz did so, hours after Khashoggi didn't come out and after consular staff informed her that he had left.

Riyadh and Ankara have also differed on the subject of the Muslim Brotherhood in Egypt and on the Israeli-Palestinian conflict, where Saudi Arabia has unofficially backed the so-called United States "deal of the century", whereas Turkey has condemned the Trump administration's attempt to "force a deal on the Palestinians".